Tropical Revolving Storms and factors affecting it

Tropical Revolving Storms are areas of tropical parts which have a severe low pressure systems. In atmosphere they are viewed as a whirl or vortex. TRS( Tropical Revolving Storms) have different names in different parts of the world. It is called as hurricane in Atlantic Ocean, Tyhoons in Pacific Ocean, Willy Willy in Australian region, cyclonic storms in Indian region, baguio in philippines and taifu in Japan. TRS forms the warm parts of the ocean and then moves the continents. TRS results in a very high wind speed and there are different stages of TRS classified according to the wind speed.

Different stages of TRS are :

         Area                     Wind speed

1	Low pressure area	not exceeding 17 knots.
2	Depression	17 to 27 knots
3	Deep Depression	28 to 33 knots
4	Cyclones	34 to 47 knots
5	Severe cyclones	48 to 63 knots
6	Very severe cyclone	64 to 119 knots
7	Super cyclones	120 knots and above.

Conditions for the formation of TRS :

. The temperature of the sea surface should be 27 degree Celsius or more to maintain a steep lapse rate in troposphere so that the vertical circulation is maintained.

. Fair amount of coriolis force is required.

At equator the coriolis force is minimum, therefore no TRS takes place at the equator or 5 degree north or south of the equator. Most of the storms takes place at a range of latitude 10 - 20 degrees North or south. Maximum cyclonic development takes place at latitude 15 degree.

. Low pressure areas surrounded by areas of high pressure is required.

. Air should rise continuously so that condensation which occurs due to adiabatic cooling results in releasing latent heat and this provides energy for the TRS.

. Prevailing winds should be weak. If the winds are strong the air will not rise vertically and will be carried off horizontally. This results in TRS not to form.

. High humidity is required for the formation of TRS. TRS Forms with warm air below 5000 ft and steep lapse rate aloft.